My cats did a shocking amount of damage to my young Chilopsis before I paid attention. The chicken wire isn't pretty, but it allowed the tree to heal on its own.
As a deterrent, I snagged a couple of logs from a neighbor who was removing a tree — approx 5" diameter by three feet — and propped them securely against a nearby fence. The cats still use them after four years and don't bother any living trees!
